About the name of planets, I think the naming them by numbers could work only if the structure of the solar system is known by everyone. {pavyplini} or {plini.xipa} (the . is mandatory since {plinixipa} might be mistaken for a fu'ivla) could work. In fact, jbovlaste already has {pavyplini} and friends.
That said, I don't like this naming scheme very much, I'd like to have some cmene for planets in our solar system. I would be tempted to use the greek/latin names as basis but I would really like to have someone who could inject some Arabic or Chinese into it.
Our moon has already a lojban word {lunra} that means "x1 is a major natural satellite/moon of planet x2" (by default our Moon). Jbovlaste also offers a word (a fu'ivla) for a generic satellite: {mluni} "x1 is a satellite/moon orbiting x2".
If you like the numbering scheme probably {lunra.xivore} could be the second moon of Mars. What I don't really like of using numbers is that it assumes a precise knowledge of the entire system: which moon of Jupiter is Io ?
A carbon nanotube could be a {navtabytu'u} and a space elevator a {kensa galgau}.
For the asterorid belts, I would try {plinyspi djine} (ring of planet fragments).
Lastly (take it "cum grano salis") {lo nundoifli cu mibysnadygau} for "your failure makes my success.
remod
btw, does you Sci-Fi occours inour solar system?